In the past, the semiconductor industry used various different device structures and methods to form semiconductor devices such as, for example, diodes, Schottky diodes, Field Effect Transistors (FETs), High Electron Mobility Transistors (HEMTs), etc. Devices such as diodes, Schottky diodes, and FETs were typically manufactured from a silicon substrate. Drawbacks with silicon based semiconductor devices include low breakdown voltages, excessive reverse leakage current, large forward voltage drops, unsuitably low switching characteristics, high power densities, and high costs of manufacture. To overcome these drawbacks, semiconductor manufacturers have turned to manufacturing semiconductor devices from compound semiconductor substrates such as, for example, III-N semiconductor substrates, III-V semiconductor substrates, II-VI semiconductor substrates, etc. Although these substrates have improved device performance, they are fragile and add to manufacturing costs.
Typically, compound semiconductor substrates are comprised of a plurality of layers of semiconductor material. For example, a compound semiconductor substrate may include a substrate layer, a nucleation layer, a buffer layer, a channel layer, and a strained layer. A drawback with these structures is that donors at the interfaces between the layers increases the leakage current by orders of magnitude. In embodiments in which the substrate layer is silicon, an inversion channel at the interface of the silicon and the nucleation layer causes leakage to the sidewalls of the semiconductor die. A III-N compound semiconductor material that includes an isolation implant to reduce leakage currents caused by metal contacting the peripheral edges of a semiconductor die has been described in U.S. Patent Application Publication Number 2013/0099324 A1 by Jenn Hwa Huang et al. and published on Apr. 25, 2013.
Accordingly, it would be advantageous to have a structure and method for manufacturing a semiconductor component to inhibit leakage currents and to improve the performance and manufacturability of semiconductor components manufactured from compound semiconductor substrates. It would be of further advantage for the structure and method to be cost efficient to implement.
For simplicity and clarity of illustration, elements in the figures are not necessarily to scale, and the same reference characters in different figures denote the same elements. Additionally, descriptions and details of well-known steps and elements are omitted for simplicity of the description. As used herein current carrying electrode means an element of a device that carries current through the device such as a source or a drain of an MOS transistor or an emitter or a collector of a bipolar transistor or a cathode or anode of a diode, and a control electrode means an element of the device that controls current flow through the device such as a gate of an MOS transistor or a base of a bipolar transistor. Although the devices are explained herein as certain n-channel or p-channel devices, or certain n-type or p-type doped regions, a person of ordinary skill in the art will appreciate that complementary devices are also possible in accordance with embodiments of the present invention. It will be appreciated by those skilled in the art that the words during, while, and when as used herein are not exact terms that mean an action takes place instantly upon an initiating action but that there may be some small but reasonable delay, such as a propagation delay, between the reaction that is initiated by the initial action. The use of the words approximately, about, or substantially means that a value of an element has a parameter that is expected to be very close to a stated value or position. However, as is well known in the art there are always minor variances that prevent the values or positions from being exactly as stated. It is well established in the art that variances of up to about ten percent (10%) (and up to twenty percent (20%) for semiconductor doping concentrations) are regarded as reasonable variances from the ideal goal of being exactly as described.